There is a decolorizing apparatus which decolorizes an image formed on a sheet. The decolorizing apparatus heats the sheet at a predetermined temperature or higher. Consequently, the image formed on the sheet is decolorized.
Meanwhile, an ink jet type apparatus, which prints an image on a sheet with a magnetic body called a magnetic sheet attached thereto, is commonly used. The magnetic sheet is much more expensive than paper, and thus repeated use thereof is desirable. For this reason, an image may be formed on a magnetic medium with decolorable toner, but if the formed image is decolorized, the magnetic medium is required to be heated at a predetermined temperature or higher. However, if the magnetic medium is heated at the predetermined or high temperature, the magnetism of the magnetic medium may be weakened.